City, who claim they have "irrefutable evidence" backing their case, are appealing against their two-year ban from European competition for Financial Fair Play breaches.
Manager Guardiola, who last week said he was committed to the club, claims to have seen this evidence and is strongly backing the fight against the UEFA-imposed sanction.
Winger Raheem Sterling – who was recently linked with Real – is poised to return to action at the Bernabeu after three weeks out with a hamstring injury.
Guardiola said: "His natural condition, his regeneration is amazing. He said to us he could have played against West Ham and Leicester but the doctor said, 'Be careful'.
"But he wanted to play and that's a good sign. He's fit, he's ready."